Archaea

Wikipedia Abstract

The Archaea (/ɑrˈkiːə/ or /ɑrˈkeɪə/ ar-KEE-ə or ar-KAY-ə; singular archaeon) constitute a domain or kingdom of single-celled microorganisms. These microbes are prokaryotes, meaning that they have no cell nucleus or any other membrane-bound organelles in their cells.Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this classification is outdated.